Add JSNative utility class with static methods methods to efficiently manipulate typed JSInterop ob…

runtime/bin/builtin.h

Index: runtime/bin/builtin.h
diff --git a/runtime/bin/builtin.h b/runtime/bin/builtin.h
index 5029cf1b30c2350b8f8ef866c3da5fe7ad3e1693..d90223af7344c01810f27fe86010828ea784b8bb 100644
--- a/runtime/bin/builtin.h
+++ b/runtime/bin/builtin.h
@@ -74,6 +74,7 @@ class Builtin {
   static const char* html_source_paths_[];
   static const char* html_common_source_paths_[];
   static const char* js_source_paths_[];
+  static const char* js_util_source_paths_[];
   static const char* blink_source_paths_[];
   static const char* indexeddb_source_paths_[];
   static const char* cached_patches_source_paths_[];